JP2006207723A - Vibration eliminating mount - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vibration eliminating mount using a flexible vibration control material for maintaining vibration eliminating and controlling performance. <P>SOLUTION: The vibration eliminating mount comprises a combination of a pair of flanges 1a, 1b, a coil spring 2 and the vibration control material 3. The pair of flanges 1a, 1b serve as an installation base for the vibration eliminating mount 11 and a supporting base for a structure. The coil spring 2 is an elastic support for the structure whose vibration is eliminated. The vibration control material 3 has certain-thickness plate mounting seats 4 at both ends, both mounting seats 4, 4 being joined to each other with a viscoelastic band portion 5. To the coil spring 2, a function is imparted which supports the weight of the structure whose vibration is eliminated. To the vibration control material 3 combined with the coil spring 2, a function is imparted which solely converts vibration energy propagating from one end to the other end of the coil spring to heat energy with only bending and stretching motion following the flexion of the coil spring 2 to decrease the vibration energy. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a vibration isolation mount that prevents the influence of extraneous vibrations on precision devices mounted on a table.

  When it is not desired to transmit the extraneous vibration transmitted through the floor to precise equipment, a vibration isolation mechanism (vibration isolation mount) is used to install the equipment. In devices where accuracy of 1 μm or less is a problem, such as IC exposure machines that form circuit patterns for electronic devices used in computers and communication equipment, and three-dimensional measuring instruments that read circuit patterns, the effects of self-excited vibrations and external vibrations There is a high need for prevention, and the performance of the vibration isolation mechanism that attenuates vibration transmitted from the floor to the equipment is an important factor that affects the performance of the machine.

  Generally, a vibration isolation mechanism having a structure incorporating an air spring has been used. In particular, by using a diaphragm type air spring having a natural frequency of 1 to 2 kHz, the function of the vibration isolation mechanism is realized by a system of the air spring and the mass of devices supported by the air spring.

  The advantage of using an air spring is that an auxiliary tank is attached and an orifice is placed between the air spring and the tank, so that attenuation due to the viscous resistance of air can be obtained, and the resonance peak at the natural frequency is lowered. This makes it possible to suppress the vibration of the support load due to disturbance.

  On the other hand, as an anti-vibration mechanism that obtains an anti-vibration function in the vertical and horizontal directions without using an expensive air spring, an apparatus (vibration mount) using a combination of a coil spring and a damping material is known. . For example, as shown in FIG. 13, this device uses a combination of a coil spring 31 and a columnar viscoelastic body (epoxy resin) as the damping material 32, and the damping material 32 is placed in the space of the coil spring 31. The flange 33 is attached to both ends of the damping material 32 and both ends of the coil spring 31, and the elastic center in the load direction acting on the composite of the coil spring 31 and the viscoelastic body 32 is included in the damping material side. The two are tightened together with screws.

  If this apparatus is used for vibration isolation support of a machine instrument, a great vibration damping effect can be obtained with respect to an external force applied in the horizontal direction (lateral direction) and the vertical direction (longitudinal direction) (see Patent Document 1).

  By the way, in the structure of the vibration isolation mount shown in FIG. 12, the load applied to the vibration isolation mount is supported by the coil spring, but the resistance from the vibration damping material cannot be ignored. The greater the deflection stroke of the coil spring, the greater the resistance of the damping material, resulting in a substantially elastic body, and the load is supported by the coil spring and the viscoelastic body. The action of gravity changes and the damping effect changes. For this reason, particularly in the case of a vibration isolation mount that supports a light load, there arises a problem that the ratio of sharing the load increases and the vibration damping performance greatly changes.

JP 63-30628 A

  The problem to be solved is that a cylindrical viscoelastic body is used for the vibration damping material of the vibration isolation mount by combining the coil spring and the vibration damping material, and the viscoelastic body is installed in the space of the coil spring. In the combined structure, the greater the deflection of the coil spring beyond the predetermined support load, the greater the proportion of the support load borne by the viscoelastic body and the greater the vibration damping performance expected of the vibration isolation mount. It is a point.

  The present invention provides an anti-vibration mount that is particularly suitable for light loads, and uses a flexible viscoelastic body as a damping material, and the damping material has one end of a coil spring mainly due to vibration of the structure. The vibration isolation mount has the function of damping the vibration energy by converting the vibration energy propagating from one end to the other into thermal energy so that it is hardly affected by the resistance of the viscoelastic body in the compression direction of the coil spring. The main feature is maintaining the vibration isolation and vibration control performance.

  According to the vibration isolation mount of the present invention, even if the load acting on the vibration isolation mount changes and a large stroke displacement occurs in the deflection of the coil spring, the vibration isolation mount is not affected by the resistance of the vibration damping material. The initial damping performance can be demonstrated. The vibration damping material may be a viscoelastic body such as a band, a spiral, or a hollow bellows, and the vibration isolation / vibration performance of the vibration isolation mount is the same as the band-like viscosity used for the vibration damper. By changing the width, thickness, and hardness of the elastic body, and by changing the shape of the shear surface, the cross-sectional area, the length of the helix, and the viscoelastic properties when using a helical viscoelastic body, When a bellows-like hollow viscoelastic body is used, it can be easily adjusted by changing the bellows shape, film thickness, number of wrinkles, and viscoelastic properties.

  The purpose of exerting the damping / vibration performance of the damping material regardless of the magnitude of the deflection deformation stroke of the coil spring is to use the flexible damping material to affect the resistance of the coil spring. This is achieved by combining a damping material with a coil spring so that there is no problem.

  Embodiments of the present invention will be described below with reference to the drawings. 1A and 1B, a vibration isolation mount 9 according to the present invention is a combination of a pair of flanges 1a and 1b, a coil spring 2, and a damping material 3. The pair of flanges 1a and 1b are arranged above and below the coil spring 2, the upper flange 1a is a support for the structure, and the lower flange 1b is a base for mounting the vibration isolation mount on the floor or table. It will be.

  The coil spring 2 is an elastic support body of a structure to be isolated, and is installed between the opposing surfaces of both flanges 1a and 1b. The damping material 3 does not become a resistance as a support against the load and vibration acting on the coil spring 2, but exclusively absorbs vibration energy propagating from one end of the coil spring to the other end with the vibration of the structure. It has a function to convert vibration energy and attenuate vibration energy. In the present invention, the viscoelastic body includes a substance that not only affects the magnitude of stress but also the increase speed of the viscoelastic body (published by the University of Science P.1059 Maruzen Co., Ltd.) Is used. An example of a material having such properties is neoprene rubber. The viscoelastic body used in the present invention is incorporated in the form of a plate or film. In this embodiment, as shown in FIGS. 2 (a) and 2 (b), a band-shaped portion 5 having mounting seats 4 and 4 at both ends is used.

  The mounting seat 4 has a spring hole 6. The spring hole 6 is an opening that receives the upper end portion or the lower end portion of the coil spring 2. In FIG. 1, the belt-like portion 5 of the damping material 3 is bent into a C shape to hold the mounting seats 4 and 4 at both ends in a vertically parallel posture, and the upper and lower ends of the coil spring 2 are fitted in the spring holes 6. The mounting seats 4 and 4 of the damping material 3 are attached to the opposing surfaces of the flanges 1a and 1b, respectively, the two flanges 1a and 1b are connected by a chain 8 slightly shorter than the height of the coil spring 2, and the coil spring 2 is slightly compressed. In this state, the coil spring 2 and the damping material 3 are assembled together on the flanges 1a and 1b. Thereby, the damping material 3 is connected to the upper end and the lower end of the coil spring 2.

  FIGS. 3A and 3B are views showing a state where the four corners of the structure 7 are supported by vibration isolation by the vibration isolation mount 9 according to the first embodiment. One flange 1a is placed on the floor (or table) as an installation stand, and the structure 7 is supported thereon using the other flange 1b as a support stand. The example of FIG. 3 is an example of installation on the structure 7 having a rectangular bottom surface. In the embodiment, the vibration damping material 3 is arranged at a position on the diagonal line of the vibration isolation mount 9 in such a posture that the vibration damping material 3 faces outward at the corners of each side.

  Further, by arranging the vibration isolation mount 9 at a position on the diagonal line of the structure, a balance of the vibration isolation characteristics in the horizontal direction is ensured. Further, by directing the damping material 3 to the corners on each side, the adjustment becomes easy when changing the width and thickness of the band-like portion of the damping material 3. The weight of the structure 7 is applied to the vibration isolation mount 9, and the coil spring 2 bends according to the size of the weight received as a weight support and reduces its height. It only follows the change by bending and stretching with respect to the expansion / contraction displacement, and it does not greatly affect the weight support.

  In the above FIGS. 1-3, although the example which made it project on one side between both flanges 1a and 1b of the vibration isolation mount 9 and was connected with the strip | belt-shaped damping material 3 was shown, It is not restricted to one place, but can be connected to the upper and lower ends of the coil spring 2 by strip-shaped damping materials 3a and 3b projecting at two places on both sides of both flanges 1a and 1b as shown in FIG.

  In this case, it is not always necessary to use two viscoelastic bodies for the strip-shaped damping materials 3a and 3b projecting on both sides of the flange, and one annular viscoelastic body is used, and a part of the viscoelastic body is used as the flange 1a, By attaching to 1b, the damping material can be extended on both sides of the flanges 1a and 1b. Even in this case, the band-shaped portions of the vibration damping materials 3a and 3b are bent in a C shape and both ends thereof are connected to the upper end and the lower end of the coil spring when assembled in the vibration isolation mount. Is exactly the same as the example of FIG. It is free to project two or more damping materials.

  A vibration isolation mount 11 of Example 2 is shown in FIG. In this embodiment, a helical viscoelastic body is used for the damping material 12. In this embodiment, as shown in FIG. 5B, a part of the cylinder 13 of the viscoelastic body is cut into a spiral shape, whereby the spiral portion 14 is formed in a certain range from the upper end of the cylinder 13 downward. The viscoelastic body which has is used.

  As shown in FIG. 5, a cylinder 13 of a viscoelastic body having a spiral portion 14 is arranged on the outer periphery of a coil spring 15 and combined concentrically inside and outside, and the combination is between an upper cap 16 and a lower cap 17 that also serve as a flange. The upper and lower ends of the damping material 12 are attached to the upper cap 16 and the lower cap 17, respectively, the coil spring 15 is slightly compressed, and the lower caps 16 and 17 are connected with, for example, a ball chain 18 to form a spiral. A gap is secured between the pitches of the shaped portions 14, and the combination of the coil spring 15 and the damping material 12 is held between the upper cap 16 and the lower cap 17.

  Even when a helical viscoelastic body is used for the damping material 12, the vibration energy propagating from one end of the coil spring to the other end is mainly generated by the vibration of the structure without functioning as a support for the structure. In order to attenuate vibration energy by converting it to energy, it is necessary to have flexibility and to be connected to the upper end and the lower end of the coil spring.

  In this embodiment, the damping material bends and stretches following the expansion and contraction of the coil spring, and the pitch of the helix changes and does not resist the load and vibration acting on the coil spring. The point of attenuating the vibration energy of the coil spring that accompanies this is the same as in the case of Example 1 using a band-like viscoelastic body. In addition, in FIG. 5, although the example using the viscoelastic body which formed the helical part in a part of cylinder is shown, you may use the viscoelastic body which has a helical part over the full length. . The vibration control performance and vibration isolation performance of the vibration isolation mount are determined by the length of the spiral portion.

A vibration isolation mount 21 of Example 3 is shown in FIG. This embodiment is an example in which a bellows-like viscoelastic body is used as a damping material. FIG. 6A shows an example in which the coil spring 2 is incorporated into the bellows hollow of the damping material 23a and combined concentrically inside and outside, and FIG. 6B shows the coil spring 2 arranged on the outer periphery of the damping material 23b. In this example, the inner and outer concentric shapes are combined. In both cases, the upper and lower ends of the coil spring 2 and the bellows cylinders of the damping members 23a and 23b are fixed to the upper and lower flanges 1a and 1b together with the coil spring, respectively, and the distance between the upper and lower 1a and 1b is slightly higher than the height of the coil spring 2. It is the same as the previous embodiment in that the coil spring and the damping material are integrally assembled to both flanges 1a and 1b with the short chain 8 connected and the coil spring 2 slightly compressed. In this embodiment, if the outer diameter of the coil spring, the material of the damping materials 23a and 23b, and the thickness of the bellows are the same, the damping material 23a is naturally more flexible than the damping material 23b. The degree to which the hardness is set should be determined by the design of the vibration isolation mount, and in the compression direction of the coil spring, the bellows is expanded and displaced with a hardness that does not affect the resistance. The desired vibration isolation and vibration control performance can be obtained.
(Experimental example)
Experimental examples of the present invention are shown below. In the experiment, a sample which supported four corners of a vibration isolation table as shown in FIG. 7 by a vibration isolation mount 9 of Example 1 in which a band-shaped vibration damping material and a coil spring were combined and also served as a weight on it. 20, the load applied to the vibration isolation mount 9 was adjusted, and the vibration characteristics in the horizontal direction and the vertical direction acting on the sample 20 were measured using the vibration sensor 21. Further, as a comparative example, the same measurement was performed using a vibration isolation mount with only a coil spring without using a band-shaped damping material.

  FIG. 8 is a graph showing the vibration characteristics of Comparative Example 1 (vibration mount height: 18 mm, load 3.36 kg), and FIG. 9 is a graph showing the vibration characteristics of Experimental Example 1 (load 3.36 kg). . In both cases, (a) shows the vibration characteristics in the horizontal direction, and (b) shows the vibration characteristics in the vertical direction. As is clear from comparison between FIG. 8 and FIG. 9, according to Experimental Example 1, compared with Comparative Example 1, the vibration magnification at the resonance point can be suppressed both in the horizontal direction and in the vertical direction. It can be seen that surging is significantly improved. In Comparative Example 1, since a band-shaped damping material was not used, the height of the vibration isolation mount was 18 mm under a load of 3.36 kg. However, in Experimental Example 1, it was bent into a C shape. Since the combined damping material has spring performance, it becomes slightly higher even under the same load as in Comparative Example 1.

  Next, when the load applied to the vibration isolation mount is still 3.36 kg and the thickness of the vibration damping material is changed thickly, that is, Experiment Example 2 regarding the vibration characteristics when the spring property of the vibration damping material is increased. 10 and Experimental Example 3 is shown in FIG. Experimental Example 2 is a case where the thickness of the damping material is relatively thin, and Experimental Example 3 is a case where the thickness of the damping material is relatively thick. Incidentally, in terms of the difference in the height of the vibration isolation mount, the height of the vibration isolation mount in Experimental Example 2 was 21 mm, and the height of the vibration isolation mount in Experimental Example 3 was 23 mm. As is clear from comparison between FIGS. 10 and 11, as the thickness of the damping material is increased, the vibration magnification is reduced in both the horizontal direction and the vertical direction, and the surging characteristics are improved. There was also a tendency for the resonance point to change to the high frequency side. As for the waveform, there was a tendency that the thicker the damping material, the gentler the frequency from low to high.

(Experimental considerations)
In the present invention, the coil spring 2 is exclusively given the function of supporting the weight of the structure to be damped and damped, and the damping material 3 combined with the coil spring 2 follows the bending of the coil spring 2. Therefore, the vibration energy propagating from one end of the coil spring to the other end is converted into heat energy only, and the function of damping the vibration energy is provided.

  Therefore, according to the present invention, most of the weight of the structure 7 is received by the coil spring 2. On the other hand, since the load of the structural body 7 hardly acts on the vibration damping material 3, the weight of the structural body is larger than the predicted range, and the resistance of the vibration damping material 3 is received even if the coil spring is greatly deformed. The expected performance (resonance frequency, resonance magnification, especially resonance magnification) targeted at the time of design can be expected.

FIG. 12 shows the vibration isolation mechanism. In FIG. 12, when only the coil spring is used for the vibration isolation mount, the resonance frequency f0 in the vertical direction is approximately expressed by Expression (1).
f0 = 5 / √ Deflection (cm) (1)
Further, the vibration transmissibility (unit dB) representing the performance of the vibration isolation mount in the combination of the coil spring and the vibration damping material is expressed by the equation (2), where U is the upper end of the vibration isolation mount and D is the lower end. .
dB = 20 log U vibration / D vibration (2)

  A curve X represents the vibration transfer characteristic of the coil spring when the resonance frequency of the coil spring is f0. The damping characteristic of the coil spring rises sharply at the resonance frequency f0, and thereafter changes from the amplification region AZ to the attenuation region DZ with a surging waveform as the vibration frequency Hz increases. As shown by the curve X, the vibration isolation mount using only the coil spring has a fatal defect that not only the surging waveform appears in the frequency characteristic of the attenuation region but also the resonance magnification is high.

  A curve Y indicates the characteristics of the vibration isolation mount that is adjusted to a desirable vibration isolation performance by combining a damping material with a coil spring. As shown in the figure, the damping curve Y of the vibration isolation mount in which the damping material is combined with the coil spring increases the resonance frequency f0 'as compared to the vibration isolation mount with only the coil spring, but the surging waveform disappears and the resonance magnification is increased. The vibration transmission characteristics with excellent vibration control performance can be obtained.

  Regarding the resonance magnification, it is possible to further reduce the resonance magnification by improving the damping performance of the damping material. However, if the resonance magnification is too low, Δf = f0′−f0 increases, and as a result, the vibration frequency The damping region becomes shallow (the absolute value of the damping becomes small), resulting in a problem that the damping performance is lowered.

  The present invention uses a plate-like viscoelastic body as a damping material, and is applied to a vibration isolating mount with a light load in particular to approximate the damping characteristic of the curve Y in FIG. In the present invention, although the damping material is attached between the upper and lower flanges, most of the load applied to the upper flange is supported by the coil spring, and the damping material is affected by the load change of the structure. Therefore, the experiment example shows that the vibration isolation performance as intended can be maintained.

In the present invention, the damping characteristics of the vibration damping mount can be adjusted by the damping performance of the damping material. That is, the damping performance of the damping material is determined by the width, thickness, and hardness (viscosity) of the band-like portion of the damping material. The width, thickness, and hardness (viscosity) of the band-like portion of the damping material can be determined in advance according to the weight of the structure to be supported by the vibration isolation mount and the magnitude of the vibration. The width and thickness of the strip-shaped portion of the material can be adjusted at the time of construction on site.

  According to the present invention, the resonance frequency is smaller than that of the vibration isolation mount with only the coil spring, and the range and size of the damping region of the vibration suppression characteristics are hardly reduced, and therefore vibration isolation without reducing the vibration damping performance. An anti-vibration effect can be obtained, and an excellent effect can be obtained particularly when used for vibration isolation and anti-vibration of a relatively lightweight structure, for example, a precision instrument having a small weight.

(A) is a partial cross-sectional side view of the vibration isolation mount according to the present invention, and (b) is a cross-sectional view taken along line AA of (a). (A) is a top view of the damping material used for the vibration isolation mount of this invention, (b) is the BB sectional drawing of (a). (A) is the side view which shows the example which supported the structure with the vibration isolating mount by this invention, (b) is the figure which looked at a mode that the structure was supported from the bottom face side of the structure. 6 is a diagram illustrating another example of the first embodiment. FIG. (A) is a figure which shows the structure of the vibration isolation mount of Example 2, (b) is a figure which shows the viscoelastic body which provided the helical part in the cylinder used for the vibration isolator of the vibration isolation mount of Example 2. It is. FIGS. 5A and 5B are diagrams showing the structure of a vibration isolation mount of Example 3, wherein FIG. 5A shows an example in which a bellows-like viscoelastic body is combined on the outside of the coil spring, and FIG. An example is shown. It is a figure which shows the point of experiment. (A) is a graph of the vibration characteristics in the horizontal direction of Comparative Example 1, and (b) is a graph of the vibration characteristics in the vertical direction. (A) is a graph of the vibration characteristics in the horizontal direction of Experimental Example 1, and (b) is a graph of the vibration characteristics in the vertical direction. (A) is a graph of the vibration characteristics in the horizontal direction of Experimental Example 2, and (b) is a graph of the vibration characteristics in the vertical direction. (A) is a graph of the vibration characteristic in the horizontal direction of Experimental Example 3, and (b) is a graph of the vibration characteristic in the vertical direction. It is a figure which shows the damping characteristic of an anti-vibration mount. It is a figure which shows the structure of the anti-vibration mount described in patent document 1. FIG.

Explanation of symbols

1a, 1b Flange 2 Coil spring 3 Damping material 4 of Example 1 Mounting seat 5 Band-shaped portion 6 Spring hole 7 Structure 8 Chain 9 Vibration isolating mount 11 Vibration isolating mount 12 Damping material 13 of Example 2 Cylinder 14 Spiral Shaped part 15 Coil spring 16 Upper cap 17 Lower cap 18 Chain 19 Anti-vibration table 20 Sample 21 Vibration sensors 23a and 23b Damping material of Example 3

Claims (10)

A vibration isolation mount having a combination of a coil spring and a damping material,
The coil spring has the function of supporting the load of the structure to be exclusively isolated and damped.
The damping material is not resistant to the load acting on the coil spring, but exclusively attenuates the vibration energy by converting the vibration energy propagating from one end of the coil spring to the other with the vibration of the structure into thermal energy. Anti-vibration mount characterized by having the function of   2. The vibration damping mount according to claim 1, wherein the vibration damping material has flexibility and is connected to an upper end and a lower end of the coil spring.   The vibration damping mount according to claim 1, wherein the damping material follows the expansion and contraction of the coil spring by bending and stretching.   The damping material is a viscoelastic body having a belt-like portion, wherein the belt-like portion is bent into a C shape and both ends thereof are connected to the upper and lower ends of a coil spring. Anti-vibration mount.   The damping material is a viscoelastic body having at least a part of a spiral, and the spiral part is concentrically combined with the coil spring, and both ends thereof are connected to the upper and lower ends of the coil spring. The vibration isolation mount according to claim 1.   The damping material is a bellows-like viscoelastic body and is concentrically combined with a coil spring installed inside or outside the bellows tube, and both ends of the bellows tube are connected to the upper and lower ends of the coil spring. The vibration isolation mount according to claim 1, wherein the vibration isolation mount is one. A vibration isolation mount comprising a combination of a pair of flanges, a coil spring, and a damping material,
The pair of flanges will be the installation base for the vibration isolation mount and the support base for the structure.
The coil spring is an elastic support for the structure to be isolated, and is installed between the opposing surfaces of both flanges.
The damping material has a band-shaped part,
2. The vibration isolation mount according to claim 1, wherein the band-shaped portion of the damping material is bent into a C shape and both ends thereof are fixed to the upper and lower flanges together with the coil spring. A vibration isolation mount comprising a combination of a pair of flanges, a coil spring, and a damping material,
The pair of flanges will be the installation base for the vibration isolation mount and the support base for the structure.
The coil spring is an elastic support for the structure to be isolated, and is installed between the opposing surfaces of both flanges.
The damping material is a cylinder with a constant thickness having at least a part of a spiral, combined concentrically with a coil spring, and fixed to both upper and lower flanges together with the coil spring. The vibration isolation mount according to claim 1. A vibration isolation mount comprising a combination of a pair of flanges, a coil spring, and a damping material,
The pair of flanges will be the installation base for the vibration isolation mount and the support base for the structure.
The coil spring is an elastic support for the structure to be isolated, and is installed between the opposing surfaces of both flanges.
The damping material is a bellows-like viscoelastic body, concentrically combined with a coil spring installed inside or outside the bellows tube, and both ends of the bellows tube are fixed to the upper and lower flanges together with the coil spring. The vibration isolation mount according to claim 1, wherein the vibration isolation mount is provided.   The damping performance of the damping material is determined by the width, thickness, and hardness of the band-like portion of the damping material, and the width and thickness of the damping material are adjusted at the time of construction on site. The vibration isolation mount according to claim 1.

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